1. Technical Field
The invention relates to assembling connection between a touch panel and a signal transmission cable.
2. Related Art
A conventional touch panel module includes a transparent substrate and a touch panel overlapping thereon. A central portion of the touch panel is defined as a touch sensing area and its surround is defined as a circuit area. The circuit area is disposed with signal wires connected to the touch sensing area. The circuit area is provided with a connecting portion of an electric contact so that the signal wires can be connected to the electric contacts. The connecting portion is attached to a flexible flat cable (FFC) so as to make electric connection therebetween. As a result, signals from the touch sensing area can be transmitted to a signal processing circuit through the signal wires and FFC.
However, modern electronic devices always tend to be smaller, lighter, thinner and shorter. The structure of an electronic device becomes more and more accurate and its outline also becomes more and more various. Particularly for the design of panel, the bigger the display is and the smaller the frame is, the better a product is. To satisfy this requirement, width of the circuit area surrounding the touch panel must be reduced. However, this is seriously adverse to the circuit area with the connecting portion because layout of the signal wires will be constricted. And the size of the connecting portion must be reduced. As a result, the manufacturing accuracy and difficulty will be elevated and the yield rate will be receded. Also, the connection between a shrunk connecting portion and the FFC tends to be unstable or infirm. This will cause a problem of transmission.
U.S. patent application Ser. No. 13/572,706, which is a copending application filed by the same inventors, discloses a signal wiring arrangement of touch panel as shown in FIG. 10. In '706, the connecting portion is flexibly extended to the outside of the circuit area of the touch panel to connect with an FFC. Such an arrangement can shrink required layout space of the circuit area, narrow down frame width and enlarge the size of the connecting portion. However, a newly developed electronic device usually requires dozens of or even a hundred transmission lines. The arrangement of '706 is still at risk of line breakage and alignment error.